This invention relates generally to the fields of biochemistry and medicine. More particularly, the present invention relates to compositions and methods useful for accelerating wound healing in mammals.
Wounds (i.e., lacerations or openings) in mammalian tissue result in tissue disruption and coagulation of the microvasculature at the wound face. Repair of such tissue represents an orderly, controlled cellular response to injury. All soft tissue wounds, regardless of size, heal in a similar manner. Tissue growth and repair are biologic systems wherein cellular proliferation and angiogenesis occur in the presence of an oxygen gradient. The sequential morphological and structural changes which occur during tissue repair have been characterized in great detail and have in some instances been quantified [Hunt, T. K., et al., xe2x80x9cCoagulation and macrophage stimulation of angiogenesis and wound healing,xe2x80x9d in The surgical wound, pp. 1-18, ed. F. Dineen and G. Hildrick-Smith (Lea and Febiger, Philadelphia: 1981)].
The cellular morphology consists of three distinct zones. The central avascular wound space is oxygen deficient, acidotic and hypercarbic, and has high lactate levels. Adjacent to the wound space is a gradient zone of local anemia (ischemia) which is populated by dividing fibroblasts. Behind the leading zone is an area of active collagen synthesis characterized by mature fibroblasts and numerous newly-formed capillaries (i.e., neovascularization). While this new blood vessel growth (angiogenesis) is necessary for the healing of wound tissue, angiogenic agents generally are unable to fulfill the long-felt need of providing the additional biosynthetic effects of tissue repair. Despite the need for more rapid healing of wounds (i.e., severe burns, surgical incisions, lacerations and other trauma), to date there has been only limited success in accelerating wound healing with pharmacological agents.
U.S. Pat. No. 5,015,629 to DiZerega (the entire disclosure of which is hereby incorporated by reference) describes a method for increasing the rate of healing of wound tissue, comprising the application to such tissue of angiotensin II (AII) in an amount which is sufficient for said increase. The application of angiotensin II to wound tissue significantly increases the rate of wound healing, leading to a more rapid re-epithelialization and tissue repair. The term angiotensin II refers to an octapeptide present in humans and other species having the sequence Asp-Arg-Val-Tyr-Ile-His-Pro-Phe (SEQ ID NO:1). Angiotensin II is a known pressor agent and is commercially available.
Angiotensin III (AIII) is a biologically active compound derived from AII by removal of a single amino acid from the N-terminus of AII. Thus, AIII has the sequence Arg-Val-Tyr-Ile-His-Pro-Phe (SEQ ID NO:2). In spite of the apparent structural relatedness of AII and AIII, these molecules exhibit a range of finctional differences. For example, AII showed a biphasic effect on evoked neuronal norepinephrine release (an earlier decrease followed by a later increase), while increasing spontaneous norepinephrine release only after 12 minutes; AIII showed a biphasic effect on both evoked and spontaneous neuronal norepinephrine release [Vatta, M. S., et al. (1992), Monophasic and biphasic effects of angiotensin II and III on norepinephrine uptake and release in rat adrenal medulla, Can. J. Physiol. Pharmacol. 70:821]. Moreover, AII and AIII show differential influences on the baroreceptor-hear-reflex: AII enhances the sensitivity of the reflex, whereas AIII impairs it [Brattstrom, A., et al. (1992), Neuropeptides within the nucleus tractus solitarii modulate the central cardiovascular control process, Progress in Brain Research 91:75].
A first aspect of the invention relates to a composition that is useful for accelerating wound healing. This composition includes a suitable carrier or diluent and an amount effective to accelerate wound healing of at least one compound having at least five contiguous amino acids of a general formula that can be any one of:
R1-Arg-norLeu-R3-R4-His-Pro-R5 (SEQ ID NO:11),
R1-Arg-R2-Tyr(PO3)2-R4-His-Pro-R5 (SEQ ID NO:12),
R1-Arg-R2-homoSer-R4-His-Pro-R5 (SEQ ID NO:13) and
R1-Arg-R2-R3-norLeu-His-Pro-R5 (SEQ ID NO: 14). In these general formulae R1 is H or Asp; R2 is Val or norLeu; R3 is Tyr, Tyr(PO3)2 or homoSer; R4 is Ile or norLeu; and R5 is H, Phe or Ile.
According to one embodiment, the compound can be any of: Asp-Arg-Val-Tyr(PO3)2-Ile-His-Pro-Phe (SEQ ID NO:4), Asp-Arg-norLeu-Tyr-Ile-His-Pro-Phe (SEQ ID NO:5), Asp-Arg-Val-Tyr-norLeu-His-Pro-Phe (SEQ ID NO:6), Asp-Arg-Val-homoSer-Ile-His-Pro-Phe (SEQ ID NO:7), Arg-norLeu-Tyr-Ile-His-Pro-Phe (SEQ ID NO:9), Arg-Val-Tyr-norLeu-His-Pro-Phe (SEQ ID NO: 10) or Asp-Arg-norLeu-Tyr-Ile-His-Pro (SEQ ID NO:15). According to a different embodiment, position R5 of the general formulae is occupied by a hydrogen moiety. According to another embodiment, the compound is in a matrical or micellar solution. According to another embodiment, the compound is dispersed in the carrier or diluent at a concentration of 1 ng/ml-5,000 xcexcg/ml, or alternatively at a concentration of 10-500 xcexcg/ml, or even at a concentration of 30-200 xcexcg/ml. In a preferred embodiment, the compound is at a concentration of at least 30 xcexcg/ml in the carrier or diluent. According to still another embodiment of the invention, the carrier or diluent can be any one of: a semi-solid polyethylene glycol polymer, carboxymethyl cellulose preparations, crystalloid preparations, viscoelastics or polypropylene glycols. According to certain embodiments, the compound of the invention is disposed on a wound dressing.
Another aspect of the invention relates to a method of accelerating wound healing. This method includes the step of applying to a wound a composition that is useful for accelerating wound healing. This composition includes a suitable carrier or diluent and an amount effective to accelerate wound healing of at least one compound having at least five contiguous amino acids of a general formula that can be any one of:
R1-Arg-norLeu-R3-R4-His-Pro-R5 (SEQ ID NO:11),
R1-Arg-R2-Tyr(PO3)2-R4-His-Pro-R5 (SEQ ID NO:12),
R1-Arg-R2-homoSer-R4-His-Pro-R5 (SEQ ID NO:13) and R1-Arg-R2-R3-norLeu-His-Pro-R5 (SEQ ID NO:14). In these general formulae R1 is H or Asp; R2 is Val or norLeu; R3 is Tyr, Tyr(PO3)2 or homoSer; R4 is Ile or norLeu; and R5 is H, Phe or Ile. According to certain embodiments of the invented method, the compound applied to the wound is any one of: Asp-Arg-Val-Tyr(PO3)2-Ile-His-Pro-Phe (SEQ ID NO:4); Asp-Arg-norLeu-Tyr-Ile-His-Pro-Phe (SEQ ID NO:5); Asp-Arg-Val-Tyr-norLeu-His-Pro-Phe (SEQ ID NO:6); Asp-Arg-Val-homoSer-Ile-His-Pro-Phe (SEQ ID NO:7); Arg-norLeu-Tyr-Ile-His-Pro-Phe (SEQ ID NO:9); Arg-Val-Tyr-norLeu-His-Pro-Phe (SEQ ID NO: 10) or Asp-Arg-norLeu-Tyr Ile-His-Pro (SEQ ID NO: 15). According to another embodiment of the invention, the compound is applied in a matrical or micellar solution. According to certain embodiments of the invented method, the compound of having the specified general formula is dispersed in a suitable carrier or diluent at a concentration of 1 ng/ml-5,000 xcexcg/ml, or alternatively at 10-500 xcexcg/ml or even at 30-200 xcexcg/ml. In some versions of the invented method, the compound specified by the general formula is at a concentration of at least 30 xcexcg/ml in the carrier or diluent. The carrier or diluent can be semi-solid polyethylene glycol polymer, carboxymethyl cellulose preparations, crystalloid preparations, viscoelastics or polypropylene glycols. In certain embodiments of the invented method, the compound is administered in conjunction with a wound dressing.